Control systems are known per se for regulating a predefined travel speed (cruise control, CC) or for regulating a vehicle to vehicle distance, such as a vehicle distance warning device (adaptive cruise control, ACC). These systems regulate a predefined travel speed or a minimum distance from a preceding vehicle, without need for the driver""s intervention. To be sure, in each case the driver of the vehicle has control over all control systems, and is able to shut off the running control system using an appropriate switch. If the control system just happens to be in an accelerating or decelerating phase, the switching off interrupts this process more or less abruptly, which has the effect of influencing riding comfort.
The method according to the present invention of interrupting a speed control or vehicle to vehicle ranging of a control system has the advantage that after activating an appropriate switch, the presently active control is not abruptly stopped, but that the method strives for a setpoint value of the acceleration during deceleration as well as acceleration, using a predefined algorithm. This algorithm is picked in such a way that a soft transition is achieved from the control operation to a standby mode.
It is especially advantageous that the setpoint acceleration value in the case of propulsion is reduced according to the given algorithm and increased in the case of braking, respectively. Because of this, it is advantageously achieved that, for example, after switching off a predefined setpoint speed, the vehicle passes over into stationary travel operation without shaking or jerking motions. Correspondingly, in the braking case, it is achieved that annoying pitching motions are omitted. During night travel especially, this avoids that the headlight cone swings up and down because of the pitching motion, and that oncoming traffic participants may be blinded by headlight glare.
One beneficial method is a linear transition from control operation to standby mode using a linear function. In an alternative embodiment, using a ramp function with appropriate steps is also conceivable.
In the braking case, the control system advantageously acts on a braking unit, such as an ABS or an ESP (electronic stability program) system which gives the braking pressure for a predefined setpoint delay. Thus, according to the predefined algorithm, the braking delay can advantageously be carried out until a minimum braking pressure is achieved in the braking system. Only after that is the control system switched off, since, with a braking pressure in the range of 0, no further braking delay appears.
Correspondingly, in the case of propulsion, the control system is switched off when the minimum acceleration boundary is undershot, so that in this case, too, a soft transition to stationary travel operation takes place.
Since many modern vehicles are outfitted with an automatic transmission, it is advantageous to prevent shifting into another transmission gear until the control system has been switched off. This advantageously prevents, for example, an unnecessary roaring of the engine during shifting downwards.
It is also regarded as favorable that the method is implemented in the control system as a software program, since the software program is easy to produce, and, on the other hand, can be simply adapted to individual vehicle types. In order to save costs and effort, the software program is advantageously built into an already existing control device of the vehicle. This can be, for instance, an ESP, a vehicle to vehicle distance control or a cruise control system.